AUTHOR=Chen Michael L. , Becraft Eric D. , Pachiadaki Maria , Brown Julia M. , Jarett Jessica K. , Gasol Josep M. , Ravin Nikolai V. , Moser Duane P. , Nunoura Takuro , Herndl Gerhard J. , Woyke Tanja , Stepanauskas Ramunas TITLE=Hiding in Plain Sight: The Globally Distributed Bacterial Candidate Phylum PAUC34f JOURNAL=Frontiers in Microbiology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00376 DOI=10.3389/fmicb.2020.00376 ISSN=1664-302X ABSTRACT=

Bacterial candidate phylum PAUC34f was originally discovered in marine sponges and is widely considered to be composed of sponge symbionts. Here, we report 21 single amplified genomes (SAGs) of PAUC34f from a variety of environments, including the dark ocean, lake sediments, and a terrestrial aquifer. The diverse origins of the SAGs and the results of metagenome fragment recruitment suggest that some PAUC34f lineages represent relatively abundant, free-living cells in environments other than sponge microbiomes, including the deep ocean. Both phylogenetic and biogeographic patterns, as well as genome content analyses suggest that PAUC34f associations with hosts evolved independently multiple times, while free-living lineages of PAUC34f are distinct and relatively abundant in a wide range of environments.